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Water marks/stain marks on turned aluminum components

7% concentration mixed with demineralized water. When we are facing, we are observing some stain marks spread on the face in few components and in few components it is not observed. As we are further plating with electroless nickel, the same stain marks/water marks are highlighted in a brighter way. This is creating an aesthetic concern. Kindly suggest a remedy to avoid the stain marks observed after facing.

ANANTHARAM.S
quality engineer - Bangalore, KARNATAKA, India
2004

We are turning and facing the aluminum forgings(AL1060F) in a Mazak turning machine using (PCD-11T3-04/CNMA-16-0404) insert. The Ra requirement is 0.25 Ra.We are using Shell Dromus-B coolant oil with

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Sometimes it can be as simple as a stronger or weaker mixture can help. What is the probability that you are having an algae growing in your sump? What is the possibility that you are not changing the coolant often enough?

James Watts
- Navarre, Florida
2004

I am not familiar with your coolant. I would go to Shell tech services and ask them if this is an appropriate coolant for your process. Send them the same information that you had in this letter and include feeds and speeds.

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2004

Dear Mr Ananthram,

I believe your coolant is not working as well as it should. Move to a better coolant as you are raising the temperature too high, too quickly, and causing temper like marks on the Aluminium surface. Or try using the coolant concentrated without any dilution.

Best of luck.

Khozem Vahaanwala
Saify Ind

Bengaluru, Karnataka, India